is preferable.
According to the first opinion—that shortening is a fixed obligation—spoke Abū Ḥanīfah, his companions, and the Kūfan jurists as a body.
The second opinion was adopted by some of al-Shāfiʿī’s disciples.
The third opinion—that it is a Sunnah—was affirmed by Mālik in the most widely transmitted reports from him.
The fourth opinion—that it is a concession—was espoused by al-Shāfiʿī in his most authoritative reports, and this is the view championed by his followers.

The reason for their disagreement is that the rational import appears to clash with the wording of the transmitted texts, while the evidence of the Prophet’s practice likewise seems to oppose both the rational meaning and the literal formulation of those texts. For what is understood from allowing the traveler to shorten his prayer is that it is a concession granted on account of hardship, just as he is permitted to break the fast and is given other leniencies.

This is supported by the tradition of Yaʿlā ibn Umayyah, who said: “I said to ʿUmar, ‘Allah only says, If you fear that those who disbelieve may afflict you (Q 4:101), and I take that to refer to shortening the prayer while traveling.’ ʿUmar replied, ‘I was astonished at the same thing that has astonished you, so I asked the Messenger of Allah—peace and blessings be upon him—about it, and he said, “It is a charity that Allah has bestowed upon you, so accept His charity.”’ The purport of this report is that it is a concession.

There is also the ḥadīth of Abū Qilābah, from a man of Banū ʿĀmir, who came to the Prophet—peace and blessings be upon him—and the Prophet said to him: “Allah has lifted from the traveler the obligation of fasting and half of the prayer.” Both reports are in the two Ṣaḥīḥs. All of this indicates facilitation, concession, and the removal of hardship—not that shortening is itself obligatory, nor even that it is a Sunnah.

The text whose wording appears to contradict this rational understanding and the drift of the foregoing reports is the rigorously authenticated ḥadīth of ʿĀʾishah: “Prayer was originally prescribed as two rakʿahs, two rakʿahs. The prayer of travel remained as it was, while the prayer of residence was increased.”

The practical evidence that seems to conflict with the rational meaning and the sense of that transmitted report is the fact that every journey of the Prophet—peace and blessings be upon him—has been related with him shortening the prayer, and no sound narration shows him ever completing it. Those who concluded that shortening is a Sunnah, or an obligatory choice between two options, were driven to that view because no reliable report had reached them stating that the Prophet—peace and blessings be upon him—ever performed the full prayer in travel; and, when the matter stands thus, one is constrained to adopt one of two positions—either that it is a mandated but flexible obligation, or that it is a Sunnah—or else to declare it a fixed obligation. Yet to deem it a definitive obligation